​blivet/bliv'*t/ [allegedly from a World War II military term meaning "ten pounds of manure in a five-pound bag"] 1. An intractable problem.

2. A crucial piece of hardware that can't be fixed or replaced if it breaks.

3. A tool that has been hacked over by so many incompetent programmers that it has become an unmaintainable tissue of hacks.

4. An out-of-control but unkillable development effort.

5. An embarrassing bug that pops up during a customer demo.

6. In the subjargon of computer security specialists, a denial-of-service attack performed by hogging limited resources that have no access controls (for example, shared spool space on a multi-user system).